Pesticide Exposure Increases Parkinson's disease Risk

Pesticide exposure increases risk of Parkinson's disease in some people, according to a new study.

Researchers at UCLA found that certain pesticides up the risk of Parkinson's disease by blocking a key enzyme called aldehyde dehydrogenase (ALDH). People carrying a variant of ALDH2 gene are five times more likely to develop the condition after being exposed to pesticides than people without the variant.

Parkinson's disease is characterized by poor coordination and trembling of hands. The condition occurs when the neurons that produce a chemical called dopamine begin to degenerate.

The present study found that the risk of developing the disease depends on the genetic make-up of the individual.

"These results show that ALDH inhibition appears to be an important mechanism through which pesticides may contribute to the development of Parkinson's disease," said Jeff M. Bronstein, MD, PhD, from UCLA and one of the study authors, according to a statement from The American Academy of Neurology to Eurekalert. "Understanding this mechanism may reveal several potential targets for preventing the disease from occurring or reducing its progression."

The study was based on data from 360 people with PD and 816 people without the condition. All participants lived in three rural California counties. Researchers used information from the California Department of Pesticide Regulation to assess participants' exposure to various pesticides.

The team found that 11 pesticides in their study inhibited ALDH. These bug-killers were used in farming and belonged to either one of the four structural classes- dithiocarbamates, imidazoles, dicarboxymides and organochlorides.

Their study showed that exposure to pesticide benomyl was linked with a 65 percent increased risk of PD while dieldrin raised PD risk by six-fold. Also, participants exposed to three or more pesticides at work or home were 3.5 times more likely to develop PD than other people.

Researchers added that people with the gene variant had higher risk of the disease only when they were exposed to the bug-killers.

"In other words, having this gene variant alone does not make you more likely to develop Parkinson's," Bronstein said in the news release. "Parkinson's is a disease that in many cases may require both genetics and environmental factors to arise."

The study is published in the journal Neurology.